PLATE I. 



RECENT. 



1. Crania anomala, Mutter, nat. size. 



1". „ „ Attached valve enlarged. 



1*. ,, „ Upper valve. 



2. Argyope cistellula, S. Wood, magnified. 



3. Terebratulina caput-serpentis, Linn., sp. 



4. „ „ Young specimen, enlarged. 



5 . 5". „ „ Enlarged specimen, to show the intercalated 



plaits. 



6. ,, „ Interior of the small valve, showing the short 



annular process. 



7. Rhynchonella psittacea, Chemnitz. 



7 a . „ „ Smaller valve, showing the short calcareous appendages. 



7 b . „ „ Interior of large valve. 



8. Terebratula cranium, Mutter. 



8 a . ,, „ Interior, exhibiting the loop. 



FOSSIL. 



9. Orbicula lamellosa? Brod., nat size. 



9 fl *. „ „ Enlarged. 



10, 11. Lingula Dumontieri, Nyst, two specimens, nat. size. 



10 aS . ,, „ Interior of both valves enlarged. 



12. „ tenuis, Sow., nat. size. 



13. Argyope cistellula, S. Wood, sp., nat. size. 

 13 a \ „ „ Enlarged. 



13". „ ,, Interior of smaller valve. 



13 d . „ „ ,, of larger valve. 



14. Terebratulina, caput-serpentis, young specimen from the Crag. 

 14 aS . „ „ Enlarged. 



15. ,, ,, Young specimen. 

 15°. . „ „ Enlarged. 



16. 16". „ striatula, nat. size. 

 16*. „ „ Enlarged. 



17. 17" 6 . Terebratula bisinuata ? Lamarck. 



18. ,, grandis, Blumenbach, from Red Crag. 

 19 fli . Rhynchonella psittacea, Chemnitz, sp., from the Crag. 



